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<div class="titlepage"><div><div><h3 class="title">
<a name="boost_asio.reference.Sender"></a><a class="link" href="Sender.html" title="Sender concepts">Sender concepts</a>
</h3></div></div></div>
<h5>
<a name="boost_asio.reference.Sender.h0"></a>
        <span class="phrase"><a name="boost_asio.reference.Sender.sender_and_sender_to"></a></span><a class="link" href="Sender.html#boost_asio.reference.Sender.sender_and_sender_to">sender
        and sender_to</a>
      </h5>
<pre class="programlisting">template&lt;class S&gt;
  concept sender =
    move_constructible&lt;remove_cvref_t&lt;S&gt;&gt; &amp;&amp;
    !requires {
      typename sender_traits&lt;remove_cvref_t&lt;S&gt;&gt;::__unspecialized; // exposition only
    };

template&lt;class S, class R&gt;
  concept sender_to =
    sender&lt;S&gt; &amp;&amp;
    receiver&lt;R&gt; &amp;&amp;
    requires (S&amp;&amp; s, R&amp;&amp; r) {
      execution::connect((S&amp;&amp;) s, (R&amp;&amp;) r);
    };
</pre>
<p>
        None of these operations shall introduce data races as a result of concurrent
        invocations of those functions from different threads.
      </p>
<p>
        A sender type's destructor shall not block pending completion of the submitted
        function objects.
      </p>
<p>
        [<span class="emphasis"><em>Note:</em></span> The ability to wait for completion of submitted
        function objects may be provided by the associated execution context. —<span class="emphasis"><em>end
        note</em></span>]
      </p>
<h5>
<a name="boost_asio.reference.Sender.h1"></a>
        <span class="phrase"><a name="boost_asio.reference.Sender.typed_sender"></a></span><a class="link" href="Sender.html#boost_asio.reference.Sender.typed_sender">typed_sender</a>
      </h5>
<p>
        A sender is <span class="bold"><strong>typed</strong></span> if it declares what types
        it sends through a receiver's channels. The <code class="computeroutput">typed_sender</code> concept
        is defined as:
      </p>
<pre class="programlisting">template&lt;template&lt;template&lt;class...&gt; class Tuple, template&lt;class...&gt; class Variant&gt; class&gt;
  struct has-value-types; // exposition only

template&lt;template&lt;class...&gt; class Variant&gt;
  struct has-error-types; // exposition only

template&lt;class S&gt;
  concept has-sender-types = // exposition only
    requires {
      typename has-value-types&lt;S::template value_types&gt;;
      typename has-error-types&lt;S::template error_types&gt;;
      typename bool_constant&lt;S::sends_done&gt;;
    };

template&lt;class S&gt;
  concept typed_sender =
    sender&lt;S&gt; &amp;&amp;
    has-sender-types&lt;sender_traits&lt;remove_cvref_t&lt;S&gt;&gt;&gt;;
</pre>
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      M. Kohlhoff<p>
        Distributed under the Boost Software License, Version 1.0. (See accompanying
        file LICENSE_1_0.txt or copy at <a href="http://www.boost.org/LICENSE_1_0.txt" target="_top">http://www.boost.org/LICENSE_1_0.txt</a>)
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